Caldwell, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.4 °C (low) to 17.6 °C (high). Annual precipitation averages 1068.6 Millimeters. Caldwell is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.2 °C | 3.7 °C | 80.52 mm |
| February | -5.1 °C | 5.7 °C | 63.25 mm |
| March | -1.3 °C | 11.2 °C | 86.36 mm |
| April | 4.2 °C | 18.7 °C | 96.52 mm |
| May | 10.1 °C | 23.3 °C | 105.92 mm |
| June | 15 °C | 27.4 °C | 119.63 mm |
| July | 17.3 °C | 29.2 °C | 106.93 mm |
| August | 16.2 °C | 28.8 °C | 92.46 mm |
| September | 11.9 °C | 25.6 °C | 89.92 mm |
| October | 5.4 °C | 19.2 °C | 73.66 mm |
| November | 0.1 °C | 12.2 °C | 75.69 mm |
| December | -3.2 °C | 6.2 °C | 77.72 mm |
| Annual | 5.4 °C | 17.6 °C | 1068.58 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |